Génération Numérique d'Hologrammes : État de l'Art

National audienceThis paper reviews Computer Generated Holography techniques applied to 3D video. Using these methods, it is possible to acquire holograms of synthetic or existing scenes without physical interference between light waves. Most limitations characterizing conventional holography, namely the need for a powerful, highly coherent laser and extreme stability of the optical system are thus avoided.Cet article présente un état de l'art des méthodes de génération numérique d'hologrammes appliquées à la vidéo 3D. Les méthodes présentées permettent de générer l'hologramme d'une scène synthétique ou réelle sans passer par le processus physique réel d'interférence entre deux ondes lumineuses. Les principales limitations liées à l'holographie conventionnelle, qui sont (1) la nécessité d'utiliser une source laser cohérente et (2) l'obligation d'avoir un système optique extrêmement stable, peuvent ainsi être évitées

Génération Numérique d'Hologrammes : État de l'Art

National audienceThis paper reviews Computer Generated Holography techniques applied to 3D video. Using these methods, it is possible to acquire holograms of synthetic or existing scenes without physical interference between light waves. Most limitations characterizing conventional holography, namely the need for a powerful, highly coherent laser and extreme stability of the optical system are thus avoided.Cet article présente un état de l'art des méthodes de génération numérique d'hologrammes appliquées à la vidéo 3D. Les méthodes présentées permettent de générer l'hologramme d'une scène synthétique ou réelle sans passer par le processus physique réel d'interférence entre deux ondes lumineuses. Les principales limitations liées à l'holographie conventionnelle, qui sont (1) la nécessité d'utiliser une source laser cohérente et (2) l'obligation d'avoir un système optique extrêmement stable, peuvent ainsi être évitées

Measuring quality of omnidirectional high dynamic range content

Although HDR content processing, coding and quality assessment have been largely addressed in the last few years, little to no work has been concentrating on how to assess quality in HDR for 360 or omnidirectional content. This paper is an attempt to answer to various questions in this direction. As a minimum, a new data set for 360 HDR content is proposed and a new methodology is designed to assess subjective quality of HDR 360 content when it is displayed on SDR HMD after applying various tone mapping operators. The results are then analyzed and conclusions are drawn

Métaphores de présentation de l'information basées sur des méthodes procédurales

National audienceNowadays, 3D on the Web is limited to 3D worlds that require a standalone software independent of the Web content, or uses Web browser's add-ons. New standards, such as HTML 5 or WebGL, are in a specification phase and will soon be available, allowing the integration on the Web of 2D content with 3D content. A major challenge will then be to be able to create 3D worlds for the visualization and browsing of multimedia content, without needing to master professional 3D authoring tools, which do not allow the computation of 3D worlds evolving automatically with the information or data to be visualized. In this article, we present a software environment for the definition of information's display metaphors, taking both the structuring of data (how the user explores and discover data) and the visual aspect of the computed environment (the geometry and data representation) into account

Vers plus de contrôle pour le créateur d'images de synthèse

Quelque soit la méthode utilisée (caméra ou synthèse), le créateur d’images a une intention/esthétique a priori sur l’image qu’il souhaite créer. Il doit donc avoir à sa disposition les outils et les paramètres de contrôle associés lui permettant d’obtenir l’image souhaitée. Nos travaux portent sur l'ensemble du pipeline de création et ont pour but de proposer plus de contrôle pour le créateur. Le but est qu'il puisse obtenir plus simplement et plus rapidement les images ou les séquences d'images avec l'esthétique souhaitée

From multibody systems modeling to distributed real-time simulation

International audienceWe present an expandable simulation framework. This system, called DREAM (deformable and rigid objects efficient for simulation and modeling), provides modelling, analysis and real-time simulation tools for rigid and deformable multibody systems. DREAM modelling tool consists of a unified abstract model which integrates traditional physically based models such as rigid solids, mass-spring meshes, finite elements and particle systems. By means of Lagrange equations, DREAM computes exact motion equations in a symbolic form to allow easy analysis of such mechanisms. Afterwards DREAM generates a C++ simulation code which solves the motion equations in our real-time distributed simulation platform. The latter is composed of different layers which manage communication and synchronization between concurrent C++ simulation codes. We present theoretical, numerical and practical aspects of the simulation framework

Tone mapping high dynamic 3D scenes with global lightness coherency

International audienceWe propose a new approach for real-time Tone Mapping Operator dedicated to High Dynamic Range rendering of interactive 3D scenes. The proposed method considers the whole scene lighting in order to preserve the global coherency. This is the major contribution of our method. Indeed, most of existing Tone Mapping Operators only consider the image rendered by the camera at the current frame and simulate the Human Visual System accommodation to bright and dark luminance. Consequently, after an adaptation time, the lighting design of the 3D scene is lost. For example, two rooms with a high contrast (one dark and one bright) can be perceived with the same luminance level after adaptation. To cope with this coherency issue, we adapt an existing Tone Mapping Operator that combines (1) a global Tone Mapping Operator which takes into account the High Dynamic Range of the whole scene and (2) a viewport frame based Tone Mapping Operator that enhances the image contrast. Thus, we preserve the global lighting coherency and enhance the contrast for each rendered image. Furthermore, we present a subjective evaluation that shows that our method provides a better user experience than previous methods in the case of visualization on Head-Mounted Display